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| Noisy slant at part throttle https://www.slantsix.org/forum/viewtopic.php?t=65236 |
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| Author: | SlantSixDan [ Wed Aug 19, 2020 9:08 pm ] |
| Post subject: | Re: Noisy slant at part throttle |
Carburetor operation and repair manuals and links to training movies and carb repair/modification threads are posted here for free download. That'll get all your carb ports identified. |
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| Author: | Charrlie_S [ Thu Aug 20, 2020 4:39 am ] |
| Post subject: | Re: Noisy slant at part throttle |
Just a FYI. I had a problem with pinging on my 64 Valiant 170, 9.5 CR engine when I swapped out the points dist, for the EI dist. EI dist had a totally wrong curve for the engine. If I used enough initial advance to get a good idle, it had way too much total, and would ping like crazy. If I backed up the initial timing so it wouldn't ping, it wouldn't idle. I didn't have time to recurve the dist, so I tried a down and dirty temporary fix. I set the total timing so there was little to no ping under moderate load (unable to get good idle at that point). Then connected the vacuum can to manifold vacuum. This gave me enough advance at closed throttle to give me a decent idle, without over advancing at rpm/load. Still need to recurve the dist, but this allowed me to drive the car. |
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| Author: | sportscarclinic [ Thu Aug 20, 2020 9:39 am ] |
| Post subject: | Re: Noisy slant at part throttle |
Thanks for the tip, I think I've got it running well enough with a modified governor ported vacuum for now until I can recurve the distributor. I took a look at the carb manuals, and got to thinking it might be running to lean right at the point where it knocks on cruise/tip in. The nice thing about the van is I can drive down the highway with the doghouse and air cleaner housing removed, which allows me to really hear what the engine's doing. When I rebuilt the carb, I unknowingly tightened down the "don't even think about adjusting" hex head screw that adjusts the needle position. Figured I had nothing to lose, so I put a long allen wrench on it and ran up the highway. The carb sounded like it was laboring for fuel (hollow bogging sound) on the entrance ramp, so I unscrewed the hex head screw a couple turns while accelerating to highway speed. It seemed to help a lot, and it seems like it's improved the tip in knocking as well. The knock isn't gone completely, but it's harder to find the throttle opening that causes it. Before it knocked every time I got off the throttle after cruise, and slightly going back in. Apart from my seat-of-the-pants method, is there a best way to adjust this needle position screw once the factory setting is lost? And, I'm assuming dialing it up (loosening) is enriching the mixture? |
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| Author: | sportscarclinic [ Mon Aug 24, 2020 10:57 am ] |
| Post subject: | Re: Noisy slant at part throttle |
Just got back from the coast. Van ran better than it ever has on the way there along Rt.46 to Tillamook. No noticeable knocking even when climbing really long grades. The way back was a different story. It was running great and we decided to take Rt. 26, so we could stop in Cannon Beach on the way back. I don't know if any of you are familiar with the climb up Saddle Mountain, but it's about 5 miles of continuous climb with around 1600 feet of elevation gain. Of course on a late Sunday afternoon, the road is a continuous line of traffic heading back towards Portland, meaning I had to maintain at least 45-50 mph to not be a road hazard. The engine started knocking about halfway up. Long story short, I pulled off a couple times along the way to let the engine cool completely, but it was no use. By the time we made it to the Sunset rest stop the engine had a serious knock, actually sounded like more clatter than just a single rod. But it still had oil pressure, wasn't overheating, and was down on power but would still pull. Damage was obviously done and the engine was toast, so I had choice to either call for a tow (probably as far as Bruxton or maybe North Plains), or try to make it closer to home before it grenaded. Luckily there were only a few more smaller climbs before we made it to the four lane. The engine was knocking like holy hell, when we got to the first exit to Hillsboro off 26, but I pressed to the Johnson School road. I honestly don't think I could have driven at highway speed another mile, it was crazy loud, my wife and kids started looking pretty worried--which is unusual, since they know a road trip with dad is always going to include some mechanical drama. Finally off the highway, I crept it along at 20-25 mph all the way to North Portland, along Germantown Road and downhill through Forest Park (shifting into neutral whenever possible). We made it into the driveway, still had oil pressure, and running cool. That's one seriously tough engine! It sounded like a cement mixing drum full of brass hammers, when I started it this morning. I had a thought while driving home that some of the guys that engineered this powerplant might have had the experience of limping home during WWII in a bomber or fighter with its engine shot up, enough time to consider what they'd want to engineer into make it all the more 'bulletproof'. I'm certain now that this engine was on it's last leg, and I'm satisfied that I definitely got 'maximum mileage'. It's gonna be a good memory, and another good 'skin of my teeth' story to add to my resume. So, all and all, I'm glad I didn't chicken-out and take the Subaru wagon on this trip. Thanks again for your help guys. I learned a lot here, stuff I'll need when I find a good donor engine to drop into this van to begin its next tour of duty. |
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| Author: | wjajr [ Mon Aug 24, 2020 11:50 am ] |
| Post subject: | Re: Noisy slant at part throttle |
This tale is not unlike an episode of Roadkill! |
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